Cache/disk subsystem
US4394733A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 14, 1980 |
| Grant date | Jul 19, 1983 |
| Priority date | — |
| Expiry date | Nov 14, 2000 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F2212/312
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
One or more storage control units (SCUs) interface one or more channels with a plurality of disk drives. One or more host processors are connected to the channels. Associated with the SCUs are one or more cache storage units (CSUs) having a relatively short access time as compared to direct accessing of the disk drives. The CSUs are transparent to the user who programs the hosts as though he were addressing the disk drives directly. An SCU converts the disk address (starting address and number of words to be transferred) to a CSU address and checks a segment descriptor table (SDT) to find out if the segment or segments involved in a transfer are present in a CSU. If so, the data is transferred from the CSU to the channel. If the data is not present in a CSU, then for a read transfer command the data is obtained from the disk drive, entered into the CSU, and supplied to the host. For a write command involving a partial segment, the segment is staged from disk to CSU and the host data overlays the appropriate portion of the segment in CSU without writing the segment back to disk. The post-store method is utilized for destaging to the disk drives segments of data which have been writt…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.